I regretted resetting after about 20 minutes in my new town although I was lucky enough to get one of my dreamies right from the off, but I gave up so much like full encyclopedias and lots of gold badges which were my biggest regrets, I stopped playing after about 2 weeks as it dawned on me I truly messed up.
Then after about a year I loaded up my town and to my amazement my dreamie was still there but I lost the second I got just before I quit.
I forced myself to play and get everything back and the only thing I haven't got back is my 1 billion gold badge, and I'm working on house plots to move in future dreamies, but all is good again